Occurrence of human astrovirus associated with gastroenteritis among Congolese children in Brazzaville, Republic of Congo

Investigation of caliciviruses and astroviruses in Gabonese rodents: A possible influence of national and international trade on the spread of enteric viruses

Caliciviruses (Caliciviridae) and astroviruses (Astroviridae) are among the leading cause of non-bacterial foodborne disease and gastroenteritis in human. These non-enveloped RNA viruses infect a wide range of vertebrate species including rodents. Rodents are among the most important hosts of infectious diseases globally and are responsible for over 80 zoonotic pathogens that affect humans. Therefore, screening pathogens in rodents will be is necessary to prevent cross-species transmission to prevent zoonotic outbreaks. In the present study, we screened caliciviruses and astroviruses in order to describe their diversity and whether they harbor strains that can infect humans. RNA was then extracted from intestine samples of 245 rodents and retrotranscribed in cDNA to screen caliciviruses and astroviruses by PCRs. All the samples tested negative for caliciviruses and while astroviruses were detected in 18 (7.3%) samples of Rattus rattus species. Phylogenetic analyses based on the RdRp gene showed that all the sequences belonged to Mamastrovirus genus in which they were genetically related to R. rattus related AstVs previously detected in Gabon or in Rattus spp. AstV from Kenya and Asia. These findings suggested that transportation such as land and railway, as well national and international trade, are likely to facilitate spread of AstVs by the dissemination of rodents.

Diversity of classic and novel human astrovirus in outpatient children with acute gastroenteritis in Shanghai, China

Introduction

Human astrovirus (HAstV) is an important pathogen of acute gastroenteritis (AGE) in children. This study was aimed at investigating the diversity and epidemiology of classic and novel HAstV in outpatient children aged 0-16 years old with AGE in Shanghai.

Methods

From May 2020 to December 2022, a total of 1,482 stool samples were collected from children diagnosed as AGE from the Children's Hospital of Fudan University. HAstV was identified using pan-astrovirus consensus primers by Reverse transcription PCR.

Results

During the study period, 3.3% (49/1,482) of specimens were identified as HAstV, with a detection rate of 2.5% (37/1,482) for classic HAstV and 0.8% (12/1,482) for novel HAstV. Among the 12 novel HAstV strains, 11 (91.7%) belonged to the HAstV-MLB and 1 (8.3%) was HAstV-VA. Genotyping revealed six circulating genotypes. Strain HAstV-1 was predominant in the study population with a detection rate of 1.8% (26/1,482) followed by HAstV-MLB1 (0.7%, 10/1,482) and HAstV-4 (0.6%, 9/1,482). Of note, all the HAstV-4 strains detected in this study were close to one astrovirus strain isolated from Bactrian camels with 99.0-100.0% amino acid sequences identity. In this study, HAstV was detected in all age groups with the highest detection rate of HAstV-positive specimens observed in children older than 73 months (5.7%, 12/209).

Discussion

This study provided useful information and contributed to the molecular epidemiology of both classic and novel HAstV, which were simultaneously characterized and reported for the first time in Shanghai.

Epidemiology of pediatric astrovirus gastroenteritis in a Nicaraguan birth cohort

Background

Astrovirus is a leading cause of acute gastroenteritis in children worldwide. However, few prospective studies have analyzed astrovirus in community-dwelling pediatric populations in low-and-middle-income countries.

Methods

We assessed the incidence, risk factors, clinical characteristics, genotypes, viral coinfections and seasonality of astrovirus gastroenteritis in 443 healthy Nicaraguan children born in 2017-2018, followed for 36 months. Children were recruited from maternity hospitals and birth records in an economically-diverse neighborhood of León, the second-largest city in Nicaragua. Astrovirus-positive episodes and genotypes were identified from diarrheal specimens with reverse transcription quantitative polymerase chain reaction and Sanger sequencing.

Results

Of 1708 total specimens tested, eighty children (18%) experienced at least 1 astrovirus episode, and 9 experienced repeat episodes, mostly during the rainy season (May-October). The incidence of astrovirus episodes was 7.8/100 child-years (95% CI: 6.2, 9.8). Genotype-specific incidence of astrovirus also exhibited seasonality. Median age of astrovirus episode onset was 16 months (IQR 9, 23). Initial astrovirus episodes were not associated with protection against future episodes during the age span studied. Astrovirus cases were exclusively breastfed for a shorter period than uninfected children, and the human milk oligosaccharide lacto-N-fucopentaose-I was more concentrated in mothers of these children. Home toilets appeared to protect against future astrovirus episodes (HR=0.19, 95% CI 0.04-0.91). Human astrovirus-5 episodes, comprising 15% of all typed episodes, were associated with longer diarrhea and more symptomatic rotavirus co-infections.

Conclusion

Astrovirus was a common cause of gastroenteritis in this cohort, and future studies should clarify the role of astrovirus genotype in clinical infection severity.

Worldwide prevalence and genotype distribution of human astrovirus in gastroenteritis patients: A systematic review and meta-analysis

AIM

Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.

METHODS

Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.

RESULTS

Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I² = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).

CONCLUSION

The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.

Viral pathogens of acute gastroenteritis in Egyptian children: role of the parechovirus

BACKGROUND AND AIM

Human parechovirus (HPeV) has emerged as a pathogen associated with acute gastroenteritis (AGE).

AIM

To detect the presence of HPeV in the stool samples from Egyptian children with AGE seeking care and the possibility of its co-infection with other enteric viruses.

METHODOLOGY

One hundred stool samples were collected from children attending Mansoura University Children's Hospital with AGE. HPeV and astrovirus were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). At the same time, detection of rotavirus antigen and norovirus was achieved by enzyme-linked immunosorbent assay and rapid immunochromatographic method, respectively.

RESULTS

The most frequently detected virus was rotavirus (39%), followed by norovirus (27%), HPeV (19%), and astrovirus (12%). Interestingly, the single infection with HPeV was 5%. Among the 19 HPeV positive samples, the co-infection of HPeV with other enteric viruses was detected in 9(43.9%) for rotavirus, 7(36.8%) for norovirus, 2(10.5%) for astrovirus, in 3(15.8%) for rotavirus and norovirus and 1(5.3%) for norovirus and astrovirus. Regarding the clinical presentation, there was no significant difference between children infected with HPeV alone and those infected with viruses other than HPeV alone; fever (p = 0.3), vomiting (p = 0.12), abdominal pain (p = 0.12), and grades of severity (P = 0.82). HPeV alone infected children were of mild severity (60%), and their main presenting symptom was fever (60%).

CONCLUSIONS

Detection of HPeV as a single viral pathogen in the stool of some children with AGE showed that this virus could be a causative agent of AGE in Egyptian children. Therefore, HPeV could be included as one of the viruses screened for AGE diagnosis in children in Egypt.

High divergence of human astrovirus genotypes circulating in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand, 2017-2020

Human astrovirus (HAstV) is one of the common causes of acute gastroenteritis in children. The investigation of molecular epidemiology of HAstV is essential for monitoring the emergence and/or re-emergence of new HAstV genotypes, as well as understanding the evolution of HAstV circulating in children suffering from acute gastroenteritis. The present study aimed to investigate the prevalence and distribution of HAstVs strains circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand during 2017-2020. A total of 1500 fecal specimens collected from children with acute gastroenteritis were screened for HAstV by RT-PCR that targeted the partial RdRp in ORF1b and strains were characterized by sequencing and phylogenetic analysis. Of the 1500 fecal samples, 39 (2.6%) were positive for HAstV. Of these, both classic and novel HAstV genotypes, including classic HAstV1-HAstV5, novel HAstV-MLB1, MLB2, and HAstV-VA2, were detected. The data in this study revealed a high divergence of HAstV genotypes circulating in pediatric patients admitted to the hospitals with acute gastroenteritis in Chiang Mai, Thailand during 2017-2020.

Near-Complete Genome Sequences of Eight Human Astroviruses Recovered from Diarrheal Stool Samples of Hospitalized Children in Coastal Kenya in 2019

Here, using a sequence-independent sequencing approach (M. V. Phan, P. Hong Anh, N. Van Cuong, B. Oude Munnink, et al., Virus Evol 2:vew027, 2016, https://doi.org/10.1093/ve/vew027), we determined human astrovirus (HAstV) genome sequences from eight diarrheal stool samples collected in coastal Kenya in 2019. Phylogenetic analysis identified the following 4 genotypes: HAstV-1 (n = 4), HAstV-2 (n = 1), HAstV-3 (n = 1), and HAstV-5 (n = 2).

Paediatrics: how to manage viral gastroenteritis

Background

Viral gastroenteritis is the most common diarrhoeal disorder seen in general practice and emergency departments. This article aims to provide a narrative updated review on the evaluation and management of viral gastroenteritis in children.

Methods

A PubMed search was performed with Clinical Queries using the key term 'viral gastroenteritis'. The search strategy included clinical trials, meta-analyses, randomized controlled trials, observational studies and reviews. The search was restricted to the English literature and the paediatric population.

Results

Acute viral gastroenteritis is usually self-limiting. However, it can lead to dehydration and electrolyte imbalance if not properly treated. Adequate fluids containing physiological concentrations of glucose and electrolytes should be provided to compensate for gastrointestinal losses and cover maintenance needs. Oral rehydration therapy is as effective as intravenous (IV) fluid therapy for rehydration for children with mild-to-moderate dehydration. Measurements of serum electrolytes, creatinine and glucose are usually not necessary and should only be considered in a subset of children with severe dehydration who require hospitalization and IV therapy. Judicious use of ondansetron can increase the success rate of oral rehydration therapy and minimize the need for IV therapy and hospitalization.

Conclusion

Acute viral gastroenteritis is associated with substantial morbidity in developed countries and significant mortality in developing countries. Physicians should educate caregivers on proper personal hygiene and handwashing to prevent faecal to oral transmission of the pathogen as well as the importance of rotavirus vaccine in the prevention of rotavirus gastroenteritis. Several norovirus vaccines are currently undergoing clinical trials with promising results. It is hoped that development of an effective norovirus vaccine will further reduce the incidence of viral gastroenteritis.

Molecular study of human astrovirus in Egyptian children with acute gastroenteritis

Introduction

Human astrovirus (HAstV) has been increasingly identified as an important cause of acute gastroenteritis in young children. Limited information is available about the prevalence and genotype distribution of classic HAstV causing acute gastroenteritis in Egyptian children.

Methods

Stool samples were collected from 100 infants and children attending the gastroenterology outpatient clinic in Mansoura University Children Hospital and suffering from acute gastroenteritis during the period extending from January 2018 to January 2019. Samples were tested for HAstV using reverse transcription PCR. Genotyping was performed using type-specific reverse transcription nested PCR.

Results

Among 100 children included in this study, the detection rate of HAstV was 11% (11 patients). There was a significant difference regarding age between cases positive and negative for HAstV (p=0.005). There was a higher prevalence of HAstV in children aged one year or younger. Significant association was detected between HAstV positive cases and rural residence (p=0.002), summer season (p=0.025) and fever (p=0.017). The HAstV genotypes detected were HAstV-8 (8/11, 72.7%), HAstV-3 (2/11, 18.2%) and HAstV-2 (1/11, 9.1%).

Conclusions

This study suggests that HAstV is a common pathogen causing gastroenteritis in Egyptian children especially in rural areas. The most frequent HAstV genotype in our study was HAstV-8.